Asymmetric petasis reactions catalyzed by chiral biphenols

J Am Chem Soc. 2008 Jun 4;130(22):6922-3. doi: 10.1021/ja8018934. Epub 2008 May 7.

Abstract

Chiral biphenols catalyze the enantioselective Petasis reaction of alkenyl boronates, secondary amines, and ethyl glyoxylate. The reaction requires the use of 15 mol % of (S)-VAPOL as the catalyst, alkenyl boronates as nucleophiles, ethyl glyoxylate as the aldehyde component, and 3 A molecular sieves as an additive. The chiral alpha-amino ester products are obtained in good yields (71-92%) and high enantiomeric ratios (89:11-98:2). Mechanistic investigations indicate single ligand exchange of acyclic boronate with VAPOL and tetracoordinate boronate intermediates.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amines / chemistry*
  • Amino Acids / chemical synthesis*
  • Boronic Acids / chemistry*
  • Catalysis
  • Glyoxylates / chemistry*
  • Magnetic Resonance Spectroscopy
  • Phenanthrenes / chemistry*
  • Phenols / chemistry*
  • Spectrometry, Mass, Electrospray Ionization
  • Stereoisomerism

Substances

  • Amines
  • Amino Acids
  • Boronic Acids
  • Glyoxylates
  • Phenanthrenes
  • Phenols
  • VAPOL ligand
  • glyoxylic acid